Effect of Three-Layer Polylactic Acid/Gelatine/Polybutylene Adipate-co-Terephthalate Film with Added ^§

Nowadays, there is a growing interest in active packaging with the addition of natural extracts due to safety concerns and consumer preferences. Physalis angulata is a medicinal and edible species of the Solanaceae family and is rich in phenolic compounds. Phenolic compounds, the secondary metabolites, are synthesised and stored in all plant tissues. They can be used as plasticizers or fillers to improve the interfacial interaction between the two biopolymers and prevent the transfer of moisture and gas from the food product and extend the shelf life to some degree.

The effect of a three-layer (P/G/B) film based on polylactic acid (P), gelatine (G) and polybutylene adipate-co-terephthalate (B) incorporated or not with Physalis leaf extract (PLE) on the quality changes of fish meat powder (sample) stored at 27-30 °C (30 days) was investigated in comparison with control (uncovered), polyethylene (PE), polylactic acid, polybutylene adipate-co-terephthalate and gelatine films. The samples were sealed in a cylindrical bottle covered with the prepared films. The storage properties such as moisture content, pH, peroxide value (PV), thiobarbituric acid reactive substances (TBARS), total volatile basic nitrogen (TVB-N), changes in colour, sensory properties and volatile compounds of samples packed with the developed films were analysed.

The moisture content was lower in the sample covered with the P/G/B-PLE-7 % film throughout the storage period. However, the sample covered with PE film had the highest PV (p<0.05). TBARS, TVB-N and volatile compounds decreased in the sample covered with P/G/B-PLE-7 % on day 30 of storage. The incorporation of Physalis leaf extract into the three-layer film improved the properties of the film and extended the shelf life of fish meat powder. Thus, the addition of Physalis leaf extract to the three-layer film could serve as a biodegradable active packaging and be a promising substitute for commercial plastic films.

This is the first report on the study of chemical changes of fish meat powder covered with a three-layer (P/G/B) film incorporated with Physalis leaf extract. This will lead to a better understanding of the role of the three-layer (P/G/B) film containing Physalis leaf extract on the extension of shelf life of fish meat powder.